本文首先通过共沉淀法制备油酸修饰的磁性Fe3O4纳米粒子,并将其均匀分散于正辛烷中得到磁流体,然后利用一步细乳液聚合法合成了单分散Fe3O4@PS磁性微球。扫描电镜分析结果表明,Fe3O4的粒径在13 nm左右,所形成的Fe3O4@PS微球的粒径在120~150 nm左右;VSM测试结果显示所合成的Fe3O4@PS微球具有超顺磁性,其饱和磁化强度约为25 emu/g;Fe3O4@PS微球表面携带明显的负电荷,其表面Zeta电势为-60 mV。反射光谱测试结果表明,Fe3O4@PS分散于水中形成的胶体溶液在磁场作用下呈现出明亮的结构色,具有明显的带隙特征;随着磁场强度的变化,反射峰波长可在450 ~ 650 nm进行调谐。

In this paper,Fe3O4 nano-particles modified by oleic acid were synthesized through coprecipitation method.The Fe3O4 nano-particles were dispersed into Octane to form magnetofluid.Then,Fe3O4@PS microspheres were prepared using one step miniemulsion polymerization method.SEM results showed that the particle size of Fe3O4 nano-particles is about 13 nm and the diameter of Fe3O4@PS microspheres is 120-150 nm or so.The magnetic measurement results showed that as-prepared Fe3O4@PS microspheres possess superparamagnetism and the saturation magnetization Ms is about 25 emu/g.The surface of Fe3O4@PS microspheres is negatively charged and the Zeta potentialis -60 mV.Reflectance spectrum measurement results showed that the colloidal suspension of Fe3O4@PS in aqueous solution exhibits bright structural color and obvious band-gap features under magnetic fields.With the increase of magnetic field strength,reflectance peaks wavelength can be modulated in the range 450-650 nm.